<template>
    <div class="goods-sku">
        <dl v-for="item in goods.specs" :key="item.id">
            <dt>{{ item.name }}</dt>
            <dd>
                <div v-for="val in item.values" :key="val.name" style="float:left">
                        <img :class="{ selected: val.selected, disabled: val.disabled }"  @click="clickSpecs(item, val)" v-if="val.picture" :src="val.picture" />
                        <span :class="{ selected: val.selected, disabled: val.disabled }" @click="clickSpecs(item, val)" v-else>{{val.name}}</span>
                </div>
            </dd>
        </dl>
    </div>
</template>

<script>
import getPowerSet from './power-set'
const spliter = '★'
export default {
    name: 'XtxSku',
    data(){
        return {
            pathMap:{},
        }
    },
    watch:{
        goods:{
            deep:true,
            handler(newValue){
                // 得到所有字典集合
                this.pathMap = this.getPathMap(newValue.skus)
                // 组件初始化的时候更新禁用状态
                this.initDisabledStatus(newValue.specs, this.pathMap)
            }
            
        }
    },
    props:{
        goods:{
            type: Object,
            default:{ specs: [], skus: [] },
        }
    },
    methods:{
        // 根据skus数据得到路径字典对象
        getPathMap(skus){
            const pathMap = {};
            if (skus && skus.length > 0) {
                skus.forEach(sku => {
                // 1. 过滤出有库存有效的sku
                if (sku.inventory) {
                    // 2. 得到sku属性值数组
                    const specs = sku.specs.map(spec => spec.valueName)
                    // 3. 得到sku属性值数组的子集
                    const powerSet = getPowerSet(specs)
                    // 4. 设置给路径字典对象
                    powerSet.forEach(set => {
                    const key = set.join(spliter)
                    // 如果没有就先初始化一个空数组
                    if (!pathMap[key]) {
                        pathMap[key] = []
                    }
                    pathMap[key].push(sku.id)
                    })
                }
                })
            }
            return pathMap
        },

        // 初始化禁用状态
        initDisabledStatus (specs, pathMap) {
            if (specs && specs.length > 0) {
                specs.forEach(spec => {
                spec.values.forEach(val => {
                    // 设置禁用状态
                    val.disabled = !pathMap[val.name]
                    })
                })
            }
        },
        
        // 得到当前选中规格集合
        getSelectedArr(specs){
            const selectedArr = []
            specs.forEach((spec, index) => {
                const selectedVal = spec.values.find(val => val.selected)
                if (selectedVal) {
                    selectedArr[index] = selectedVal.name
                } else {
                    selectedArr[index] = undefined
                }
            })
            return selectedArr
        },

        // 更新按钮的禁用状态
        updateDisabledStatus(specs, pathMap){
            // 遍历每一种规格
            specs.forEach((item, i) => {
                // 拿到当前选择的项目
                const selectedArr = this.getSelectedArr(specs)
                // 遍历每一个按钮
                item.values.forEach(val => {
                if (!val.selected) {
                    selectedArr[i] = val.name
                    // 去掉undefined之后组合成key
                    const key = selectedArr.filter(value => value).join(spliter)
                    val.disabled = !pathMap[key]
                }
                })
            })
        },
        
        clickSpecs(item, val){
            if (val.disabled) return false;
            // 选中与取消选中逻辑
            if (val.selected) {
                this.$set(val,'selected',false);
                // val.selected = false;
            } else {
                item.values.forEach(bv => { 
                    // bv.selected = false 
                    this.$set(bv,'selected',false);
                });
                // val.selected = true;
                this.$set(val,'selected',true);
            }
            // 点击之后再次更新选中状态
            this.updateDisabledStatus(this.goods.specs, this.pathMap);
            // 把选择的sku信息传出去给父组件
            // 触发change事件将sku数据传递出去
            const selectedArr = this.getSelectedArr(this.goods.specs).filter(value => value)
            // 如果选中得规格数量和传入得规格总数相等则传出完整信息(都选择了)
            // 否则传出空对象
            if (selectedArr.length === this.goods?.specs.length) {
                // 从路径字典中得到skuId
                const skuId = this.pathMap[selectedArr.join(spliter)][0]
                const sku = this.goods?.skus.find(sku => sku.id === skuId)
                // 传递数据给父组件
                this.$emit('change', {
                    skuId: sku.id,
                    price: sku.price,
                    oldPrice: sku.oldPrice,
                    inventory: sku.inventory,
                    specsText: sku.specs.reduce((p, n) => `${p} ${n.name}：${n.valueName}`, '').trim()
                })
            } else {
                this.$emit('change', {})
            }
            }
    }

}
</script>

<style scoped lang="scss">
@mixin sku-state-mixin {
    border: 1px solid #e4e4e4;
    margin-right: 10px;
    cursor: pointer;

    &.selected {
        border-color: $xtxColor;
    }

    &.disabled {
        opacity: 0.6;
        border-style: dashed;
        cursor: not-allowed;
    }
    }

    .goods-sku {
    padding-left: 10px;
    padding-top: 20px;

    dl {
        display: flex;
        padding-bottom: 20px;
        align-items: center;

        dt {
        width: 50px;
        color: #999;
        }

        dd {
        flex: 1;
        color: #666;

        >div>img {
            width: 50px;
            height: 50px;
            margin-bottom: 4px;
            @include sku-state-mixin;
        }

        >div>span {
            display: inline-block;
            height: 30px;
            line-height: 28px;
            padding: 0 20px;
            margin-bottom: 4px;
            @include sku-state-mixin;
        }
        }
    }
}
</style>